
4AT(H4SO)-67
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
6 CHECK POOR CONTACT.Is there poor contact in 2-4
brake timing solenoid circuit?Repair the poor
contact.Replace the TCM.
trol Module
(TCM).>
7 CHECK 2-4 BRAKE TIMING SOLENOID (IN
TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Lift-up or raise the vehicle and support with
rigid rack.
N
OTE:
Raise all wheels off ground.
3) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
4) Remove the oil pan, and disconnect con-
nector from 2-4 brake timing solenoid.
5) Measure the resistance between 2-4 brake
timing solenoid connector and transmission
ground.
Te r m i n a l s
No. 1 — Transmission ground:Is the resistance 10 — 16 Ω? Go to step 8.Replace the 2-4
brake timing sole-
noid.
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
8 CHECK HARNESS CONNECTOR BETWEEN
2-4 BRAKE TIMING SOLENOID AND
TRANSMISSION.
Measure the resistance of harness between 2-
4 brake timing solenoid and transmission con-
nector.
Connector & terminal
(AT8) No. 1 — (T4) No. 4:Is the resistance less than 1
Ω?Go to step 9.Repair the open
circuit in harness
between 2-4 brake
timing solenoid
and transmission
connector.
9 CHECK HARNESS CONNECTOR BETWEEN
2-4 BRAKE TIMING SOLENOID AND
TRANSMISSION.
Measure the resistance of harness between 2-
4 brake timing solenoid connector and trans-
mission ground.
Connector & terminal
(T4) No. 4 — Transmission ground:Is the resistance more than 1
MΩ?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in 2-4
brake timing sole-
noid and transmis-
sion.Repair the short
circuit harness
between 2-4 brake
timing solenoid
and transmission
connector. Step Check Yes No

4AT(H4SO)-70
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Turn the ignition switch to ON (engine
OFF).
2) Throttle is fully open.
3) Read the data of line pressure duty sole-
noid using Subaru Select Monitor.Is the value less than 25%? Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in trans-
mission.Go to step 9.
9 CHECK POOR CONTACT.Is there poor contact in line
pressure duty solenoid circuit?Repair the poor
contact.Replace the TCM.
trol Module
(TCM).>
10 CHECK LINE PRESSURE DUTY SOLENOID
(IN TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
3) Remove the oil pan, and disconnect con-
nector from line pressure duty solenoid.
4) Measure the resistance between line pres-
sure duty solenoid connector and transmission
ground.
Te r m i n a l s
No. 1 — Transmission ground:Is the resistance 2.0 — 4.5 Ω? Go to step 11.Replace the line
pressure duty
solenoid.
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LINE PRESSURE
DUTY SOLENOID.
Measure the resistance of harness between
line pressure duty solenoid and transmission
connector.
Connector & terminal
(T4) No. 5 — (AT2) No. 1:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit in harness
between line pres-
sure duty solenoid
and transmission
connector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND LINE PRESSURE
DUTY SOLENOID.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 5 — Transmission ground:Is the resistance more than 1
MΩ?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in line
pressure duty
solenoid and
transmission.Repair the short
circuit in harness
between line pres-
sure duty solenoid
and transmission
connector. Step Check Yes No

4AT(H4SO)-73
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Turn the ignition switch to ON (engine
OFF).
2) Throttle is fully open.
3) Read the data of 2-4 brake duty solenoid
using Subaru Select Monitor.Is the value less than 25%? Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and transmission.Go to step 9.
9 CHECK POOR CONTACT.Is there poor contact in 2-4
brake duty solenoid circuit?Repair the poor
contact.Replace the TCM.
trol Module
(TCM).>
10 CHECK 2-4 BRAKE DUTY SOLENOID (IN
TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
3) Remove the oil pan, and disconnect con-
nector from 2-4 brake duty solenoid.
4) Measure the resistance between 2-4 brake
duty solenoid connector and transmission
ground.
Te r m i n a l s
No. 1 — Transmission ground:Is the resistance 2.0 — 4.5 Ω? Go to step 11.Replace the 2-4
brake duty sole-
noid.
noids, Duty Sole-
noids and ATF
Temperature Sen-
sor.>
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND 2-4 BRAKE DUTY SO-
LENOID.
Measure the resistance of harness between 2-
4 brake duty solenoid and transmission con-
nector.
Connector & terminal
(T4) No. 9 — (AT7) No. 1:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit in harness
between 2-4 brake
duty solenoid and
transmission con-
nector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSMISSION AND 2-4 BRAKE DUTY SO-
LENOID.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 9 — Transmission ground:Is the resistance more than 1
MΩ?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in line
pressure duty
solenoid and
transmission.Repair the short
circuit in harness
between 2-4 brake
duty solenoid and
transmission con-
nector. Step Check Yes No

4AT(H4SO)-77
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
10 CHECK POOR CONTACT.Is there poor contact in lock-up
duty solenoid circuit?Repair poor con-
tact.Replace the TCM.
trol Module
(TCM).>
11 CHECK LOCK-UP DUTY SOLENOID (IN
TRANSMISSION).
1) Remove the transmission connector from
bracket.
2) Drain the ATF.
CAUTION:
Do not drain the ATF until it cools down.
3) Remove the oil pan and disconnect con-
nector from lock-up duty solenoid.
4) Measure the resistance between lock-up
duty solenoid connector and transmission
ground.
Te r m i n a l s
No. 1 — Transmission ground:Is the resistance 10 — 17 Ω? Go to step 12.Replace the lock-
up duty solenoid.
Duty Solenoids
and ATF Tempera-
ture Sensor.>
12 CHECK HARNESS CONNECTOR BETWEEN
LOCK-UP DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between
lock-up duty solenoid and transmission con-
nector.
Connector & terminal
(T4) No. 13 — (AT3) No. 1:Is the resistance less than 1
Ω?Go to step 13.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
13 CHECK HARNESS CONNECTOR BETWEEN
LOCK-UP DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 13 — Transmission ground:Is the resistance more than 1
MΩ?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in lock-
up duty solenoid
and transmission.Repair the short
circuit in harness
between lock-up
duty solenoid and
transmission con-
nector. Step Check Yes No

4AT(H4SO)-80
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
8 CHECK OUTPUT SIGNAL EMITTED FROM
TCM USING SUBARU SELECT MONITOR.
1) Move the select lever to “N” range with
throttle fully closed (vehicle speed 0 km/h or 0
MPH).
2) Read the data of transfer duty solenoid
using Subaru Select Monitor.
Transfer duty solenoid is indicated in “%”.Is the value 5 — 10%? Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and transmission.Go to step 9.
9 CHECK POOR CONTACT.Is there poor contact in transfer
duty solenoid circuit?Repair the poor
contact.Replace the TCM.
trol Module
(TCM).>
10 CHECK TRANSFER DUTY SOLENOID (IN
TRANSMISSION).
1) Lift-up the vehicle and place rigid rack.
NOTE:
Raise all wheels off ground.
2) Drain the automatic transmission fluid.
CAUTION:
Do not drain the automatic transmission flu-
id until it cools down.
3) Remove the extension case and disconnect
connector from transfer duty solenoid.
4) Measure the resistance between transfer
duty solenoid connector and transmission
ground.
Connector & terminal
(AT4) No. 1 — Transmission ground:Is the resistance 10 — 17 Ω? Go to step 11.Replace the trans-
fer duty solenoid.
11 CHECK HARNESS CONNECTOR BETWEEN
TRANSFER DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between
transfer duty solenoid and transmission con-
nector.
Connector & terminal
(T4) No. 6 — (AT4) No. 1:Is the resistance less than 1
Ω?Go to step 12.Repair the open
circuit in harness
between transfer
duty solenoid and
transmission con-
nector.
12 CHECK HARNESS CONNECTOR BETWEEN
TRANSFER DUTY SOLENOID AND TRANS-
MISSION.
Measure the resistance of harness between
transmission connector and transmission
ground.
Connector & terminal
(T4) No. 6 — Transmission ground:Is the resistance more than 1
MΩ?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
contact in transfer
duty solenoid and
transmission.Repair the short
circuit in harness
between transfer
duty solenoid and
transmission con-
nector. Step Check Yes No

4AT(H4SO)-82
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
transmission.
3) Measure the resistance of harness
between TCM and transmission connector.
Connector & terminal
(B55) No. 24 — (B11) No. 19:Is the resistance less than 1
Ω?Go to step 2.Repair the open
circuit in harness
between TCM and
transmission con-
nector.
2 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and transmission connector.
Connector & terminal
(B54) No. 19 — (B11) No. 20:Is the resistance less than 1
Ω?Go to step 3.Repair the open cir-
cuit in harness
between TCM and
transmission, and
poor contact in cou-
pling connector.
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B55) No. 24 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 4.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND TRANSMISSION.
Measure the resistance of harness between
TCM and chassis ground.
Connector & terminal
(B54) No. 19 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the short
circuit in harness
between TCM and
transmission con-
nector.
5 CHECK REAR VEHICLE SPEED SENSOR.
Measure the resistance between transmission
connector receptacle’s terminals.
Connector & terminal
(T4) No. 19 — No. 20:Is the resistance 450 — 650
Ω?Go to step 6.Replace the rear
vehicle speed sen-
sor.
Speed Sensor.>
6 PREPARE OSCILLOSCOPE.Do you have an oscilloscope? Go to step 10.Go to step 7.
7 PREPARE SUBARU SELECT MONITOR.Do you have a Subaru Select
Monitor?Go to step 9.Go to step 8.
8 CHECK INPUT SIGNAL FOR TCM.
1) Connect the connectors to TCM and trans-
mission.
2) Lift-up or raise the vehicle and place rigid
rack.
N
OTE:
Raise all wheels off floor.
3) Start the engine and set vehicle in 20 km/h
(12 MPH) condition.
N
OTE:
The speed difference between front and rear
wheels may light the ABS warning light, but this
indicates no malfunction. When AT control diag-
nosis is finished, perform the ABS memory
clearance procedure of on-board diagnostics
system.
4) Measure the voltage between TCM con-
nector terminals.
Connector & terminal
(B55) No. 24 (+) — (B54) No. 19 (
−):Is the voltage more than AC 1
V?Even if the
POWER indicator
light was blinking,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector or
harness may be
the cause. Repair
the harness or
connector in TCM
and transmission.Go to step 11.

4AT(H4SO)-86
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
Step Check Yes No
1 CHECK FWD SWITCH.
Connect the Subaru Select Monitor to data link
connector, and then change to LED display
screen.When the fuse is inserted to
FWD switch, does LED light
up?Go to step CHECK
BRAKE SWITCH.
CHECK BRAKE
SWITCH, Diag-
nostic Procedure
without Diagnostic
Trouble Code
(DTC).>Go to step 2.
2 CHECK FWD INDICATOR LIGHT.
1) Turn the ignition switch to OFF.
2) Disconnect the TCM connector.
3) Turn the ignition switch to ON.
4) Short the combination meter connector to
chassis ground.
CAUTION:
Be sure to short through fuse.
Connector & terminal
(i10) No. 22 — Chassis ground:Does the FWD indicator light
illuminate?Go to step 3.Inspect the combi-
nation meter.
Meter Assembly.>
3 CHECK HARNESS CONNECTOR BETWEEN
TCM AND FWD SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
FWD switch.
3) Measure the resistance of harness
between TCM and FWD switch connector.
Connector & terminal
(B55) No. 20 — (F27) No. 36:Is the resistance less than 1
Ω?Go to step 4.Repair the open
circuit in harness
between TCM and
FWD switch con-
nector.
4 CHECK HARNESS CONNECTOR BETWEEN
TCM AND FWD SWITCH.
Measure the resistance of harness connector
between TCM and body to make sure that cir-
cuit does not short.
Connector & terminal
(B55) No. 20 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 5.Repair the short
circuit in harness
between TCM and
FWD switch con-
nector.
5 CHECK HARNESS CONNECTOR BETWEEN
FWD SWITCH AND CHASSIS GROUND.
Measure the resistance of harness between
FWD switch and chassis ground.
Connector & terminal
(F27) No. 35 — Chassis ground:Is the resistance less than 1
Ω?Go to step 6.Repair the open
circuit in harness
between FWD
switch connector
and chassis
ground.
6 CHECK INPUT SIGNAL FOR TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and FWD
switch.
3) Turn the ignition switch to ON.
4) Measure the signal voltage for TCM while
installing the fuse to FWD switch connector.
Connector & terminal
(B55) No. 20 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 7.Go to step 11.
7 CHECK INPUT SIGNAL FOR TCM.
Measure the signal voltage for TCM while
removing the fuse from FWD switch connector.
Connector & terminal
(B55) No. 20 (+) — Chassis ground (
−):Is the voltage 6 — 9.1 V? Go to step 8.Replace the TCM.
trol Module
(TCM).>

4AT(H4SO)-87
AUTOMATIC TRANSMISSION (DIAGNOSTIC)
Diagnostic Procedure without Diagnostic Trouble Code (DTC)
8 CHECK HARNESS CONNECTOR BETWEEN
TCM AND COMBINATION METER.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from TCM and
combination meter.
3) Measure the resistance of harness
between TCM and combination meter.
Connector & terminal
(B56) No. 2 — (i11) No. 4:Is the resistance less than 1
Ω?Go to step 9.Repair the open
circuit in harness
between TCM and
combination meter
and poor contact
in coupling con-
nector.
9 CHECK HARNESS CONNECTOR BETWEEN
TCM AND COMBINATION METER.
Measure the resistance of harness connector
between TCM and chassis ground.
Connector & terminal
(B56) No. 2 — Chassis ground:Is the resistance more than 1
MΩ?Go to step 10.Repair the short
circuit in harness
between TCM and
combination meter
connector.
10 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
1) Turn the ignition switch to OFF.
2) Connect the connector to TCM and combi-
nation meter.
3) Turn the ignition switch to ON.
4) Measure the signal voltage for TCM while
installing the fuse to FWD switch connector.
Connector & terminal
(B56) No. 2 (+) — Chassis ground (
−):Is the voltage less than 1 V? Go to step 11.Go to step 12.
11 CHECK OUTPUT SIGNAL EMITTED FROM
TCM.
Measure the signal voltage for TCM while
removing the fuse from FWD switch connector.
Connector & terminal
(B56) No. 2 (+) — Chassis ground (
−):Is the voltage 6 — 9.1 V? Go to step 12.Replace the TCM.
trol Module
(TCM).>
12 CHECK POOR CONTACT.Is there poor contact in FWD
switch circuit?Repair the poor
contact.Replace the TCM.
trol Module
(TCM).> Step Check Yes No